This invention relates to a metal thin plate produced by electrodeposition, to a method of producing the metal thin plate, and to a rotary blade cutter produced by the method.
By combining electrodeposition with lithography, it is possible to produce a metal microstructure necessary for micromachines and micro parts. In the electrodeposition, nickel is widely used as an electrodeposited metal material. This is because nickel is relatively easily electrodeposited. Therefore, it is attempted to use a metal thin plate of electrodeposited nickel for micro electronics components, such as spiral contactors, which require a spring function (see Japanese Patent Application Publication (JP-A) No. 2003-78078). However, a metal structure formed by the electrodeposited nickel has drawbacks as follows. That is, plastic deformation called creep deformation is caused even under a stress load lower than a yield stress. Furthermore, even in a relatively low temperature region at and above the room temperature, crystal grain growth occurs so that the electrodeposited nickel is softened. As a result, the spring function is gradually lost with an increase in time period of use. Furthermore, although precision electrodeposition is relatively easy, nickel is fragile and is therefore susceptible to mechanical damage. Accordingly, as a material of a high-speed rotary blade cutter, the lifetime of nickel is too short.
In the meantime, development has been made of a technology of producing a nickel-tungsten (Ni—W) alloy thin plate by electrodeposition as an ideal material which compensates for the above-mentioned mechanical disadvantages of nickel (see Japanese Patent Application Publication (JP-A) No. 2001-342591). However, the nickel-tungsten alloy has an electrical conductivity corresponding to only about one tenth of that of nickel. Thus, the nickel-tungsten alloy has a critical defect for use as an electro-conductive material. Furthermore, the nickel-tungsten alloy is low in alkali resistance though high in acid resistance.